1. Field of the Invention
The present invention pertains to electrostatic printing, and more particularly, pertains to a non-corrosive corona wire and method of terminal securement to the end points of the non-corrosive corona wire.
2. Description of the Prior Art
Current technology typically uses a small diameter tungsten wire, such as a 0.003 inch diameter wire having a coating of vitrified carbon about its surface which provides a small degree of corrosion protection to the encompassed tungsten wire from the high concentration of O.sub.3 which is generated by the corona about the wire when used in a xerographic process. The vitrified carbon coating around the wire is in general a dry graphite lubricant which remains from the drawing process. Any breaks, thin spots or unevenness in this vitrified carbon coating can and will expose the underlying tungsten wire to the ozone in the corona, and consequently, oxidizing the tungsten to WO.sub.2. This oxidized area, particularly in a humid environment, will virtually increase the tungsten wire diameter, thus altering the surface geometry resulting in a nonlinear distribution of the electrostatic charge. The electrostatic charge gradient will consequently cause density gradients and aberrations in the completed copy.
The present invention overcomes the problems encountered in the prior art by providing a noble metal plated tungsten wire and a method of termination securement whereby the inert noble metal surface protects the tungsten from an ozone attack.